From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-0.9 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI, SPF_HELO_NONE,SPF_PASS autolearn=no autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id BBA9BC433E0 for ; Tue, 16 Jun 2020 20:29:06 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 926F92085B for ; Tue, 16 Jun 2020 20:29:06 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=redhat.com header.i=@redhat.com header.b="QVwD5v87" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1731758AbgFPU3E (ORCPT ); Tue, 16 Jun 2020 16:29:04 -0400 Received: from us-smtp-delivery-1.mimecast.com ([205.139.110.120]:35123 "EHLO us-smtp-1.mimecast.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1731425AbgFPU3D (ORCPT ); Tue, 16 Jun 2020 16:29:03 -0400 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1592339341; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=PuFuQg6K4e8+oPcKh4HKkSbhQEN3+Z7Dt+MuhnK0tiM=; b=QVwD5v87tlgcmO4H0p8qZurzxWvn6QmqBeyqbDRtKeXm4tFXkyLPpjZ3XnAY9riho2g2cp nF3rdHH9bQwamlM3P9ob1KD/fre+Xt33qE1T+xfJOXz78e13yiEvjGwRE1jemMW6TJ29ev Aruavogdm7ehUHavpB5yqulk0Tp6Q2Q= Received: from mimecast-mx01.redhat.com (mimecast-mx01.redhat.com [209.132.183.4]) (Using TLS) by relay.mimecast.com with ESMTP id us-mta-396-g5CUkErUN0yKgA33gmgSYw-1; Tue, 16 Jun 2020 16:28:59 -0400 X-MC-Unique: g5CUkErUN0yKgA33gmgSYw-1 Received: from smtp.corp.redhat.com (int-mx05.intmail.prod.int.phx2.redhat.com [10.5.11.15]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx01.redhat.com (Postfix) with ESMTPS id F1AF58AB398; Tue, 16 Jun 2020 20:28:52 +0000 (UTC) Received: from x2.localnet (ovpn-113-201.phx2.redhat.com [10.3.113.201]) by smtp.corp.redhat.com (Postfix) with ESMTP id 06D8D6C1A0; Tue, 16 Jun 2020 20:28:51 +0000 (UTC) From: Steve Grubb To: Mimi Zohar Cc: Lakshmi Ramasubramanian , Paul Moore , rgb@redhat.com, linux-integrity@vger.kernel.org, linux-audit@redhat.com, linux-kernel@vger.kernel.org Subject: Re: [PATCH 1/2] integrity: Add errno field in audit message Date: Tue, 16 Jun 2020 16:28:47 -0400 Message-ID: <2644117.Ritcz3IfYv@x2> Organization: Red Hat In-Reply-To: <1592337220.11061.239.camel@linux.ibm.com> References: <20200611000400.3771-1-nramas@linux.microsoft.com> <1717101.NiBDiG0Zly@x2> <1592337220.11061.239.camel@linux.ibm.com> MIME-Version: 1.0 Content-Transfer-Encoding: 7Bit Content-Type: text/plain; charset="us-ascii" X-Scanned-By: MIMEDefang 2.79 on 10.5.11.15 Sender: linux-integrity-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-integrity@vger.kernel.org On Tuesday, June 16, 2020 3:53:40 PM EDT Mimi Zohar wrote: > On Tue, 2020-06-16 at 11:55 -0400, Steve Grubb wrote: > > On Tuesday, June 16, 2020 11:43:31 AM EDT Lakshmi Ramasubramanian wrote: > > > On 6/16/20 8:29 AM, Steve Grubb wrote: > > > >>>>> The idea is a good idea, but you're assuming that "result" is > > > >>>>> always errno. That was probably true originally, but isn't now. > > > >>>>> For example, ima_appraise_measurement() calls xattr_verify(), > > > >>>>> which compares the security.ima hash with the calculated file > > > >>>>> hash. On failure, it returns the result of memcmp(). Each and > > > >>>>> every code path will need to be checked. > > > >>>> > > > >>>> Good catch Mimi. > > > >>>> > > > >>>> Instead of "errno" should we just use "result" and log the value > > > >>>> given in the result parameter? > > > >>> > > > >>> That would likely collide with another field of the same name which > > > >>> is the operation's results. If it really is errno, the name is fine. > > > >>> It's generic enough that it can be reused on other events if that > > > >>> mattered. > > > >> > > > >> Steve, what is the historical reason why we have both "res" and > > > >> "result" for indicating a boolean success/fail? I'm just curious > > > >> how we ended up this way, and who may still be using "result". > > > > > > > > I think its pam and some other user space things did this. But > > > > because of mixed machines in datacenters supporting multiple versions > > > > of OS, we have to leave result alone. It has to be 0,1 or success/ > > > > fail. We cannot use it for errno. > > > > > > As Mimi had pointed out, since the value passed in result parameter is > > > not always an error code, "errno" is not an appropriate name. > > > > > > Can we add a new field, say, "op_result" to report the result of the > > > specified operation? > > > > Sure. But since it is errno sometimes, how would we know when to > > translate it? > > Perhaps the solution is not to imply "res" is "errno", but pass it as > a separate "errno" field. That's what is done on syscalls. There is success and exit where they both have different meaning sometimes but otherwise they agree. > Then only include "errno" in the audit message when it isn't zero. This > assumes that some audit messages for the same audit number include errno, > while others do not. We normally do not like to have fields that swing in and out because then its hard to know exactly what's in the event. When an event has different fields under special conditions, then we just say call it a new event. Split it into 2 or 3 instead forcing it all into 1. And we also do not like fields that change meaning. Because then intepretation becomes hard. Or other people wishing to record the same info in another event have to follow the same pattern. So, if you really need this field, the give some name like err_code or errno or anything not taken. And just fill it out every time. Its OK to be 0. If this only happens under some special operation, then make it a new event and fill it out only for that operation/event. Best Regards, -Steve > With this solution, the existing integrity_audit_msg() could become a > wrapper for the new function. > > Mimi